Thematically, since SC1, Protoss has always been my "favorite" race, although as a rule of thumb I always play Random for the variety. In SC2, I am increasingly finding it to be the most boring in terms of strategic and unit variety.
Terran is obviously multilinear (even TvT is good). All of their units are viable in most matchups. A million great harassment options.
Zerg seems linear at first, but advanced play actually forces you into some exotic strategies. There isn't a unit that doesn't see regular use for me. Only complaint is that ZvZ doesn't have a very good metagame and stays in T2 units. And of course, Zerg is just different a playstyle and interface than the other two.
Protoss...quite linear IMO. Get 3-4 gates and Robo is definitely 90% of games you see. Other paths far more vulnerable and not sustainable once opponent figures out what's up. Stalker/Collosus tends to predominate other options. Motherships, Carriers, Archons...totally unused. Even Phoenix (yes I know the Nony uses and strats) don't have that many applications.
Just my opinion. I had more fun with Reaver Drops and Arbiter fleets than the (admitedly effective) attack-move Protoss Ball.
Wut? Stargate is extremely Viable against Zerg, you can defend against Mutas in a better Way, can net you Map control, you can harass.
Templar Tech is quite Good against Zerg too. Of course the Protoss player will need to have some core units(Gateway) but against Zerg all 3 paths have some use.Colossi tech is more popular because it requires less micro, but its more counterable.
Against Terran(Because of the dominance of a cloaked Banhsee of you are not prepared) Robo is a must, I do think that the Banshee cloak will need to be nerfed at some point, because the pure threat of it forces a tech path.
As for PvP some people are now experimenting away from the Robo builds dominant in that MU. I'd say we leave the game some time to eveolve
My 2 Cents.
http://www.backloggery.com/main.php?user=Windsupernova Play Whatever. No fanboyism. PW.President of the Biased club
I actually don't disagree with anything u said. But only ZvP really opens up some of these other options.
The Robo path is a must against Terran and Protoss.
As you mentioned, there's no detection along other paths, and Collosus is too crucial in most cases. PvP would benefit from a better way to snipe Collosi (which Terran and Zerg have). I've always felt like there needed to be some kind of weak detection along the templar path. Let Archon's automatically attack cloaked units or something.